Evaluation on the Efficacy and Safety of Panax Notoginseng Saponins in the Treatment of Stroke among Elderly People: A Systematic Review and Meta-Analysis of 206 Randomized Controlled Trials

Background Evidence regarding the effect of Panax notoginseng saponins (PNS) on treating elderly stroke patients is scare and inconsistent. This study investigated the efficacy and safety of PNS by means of meta-analysis so as to provide an evidence-based reference for the treatment of elderly patients with stroke. Methods We searched the PubMed, Embase, Cochrane Library, Web of Science, CNKI, VIP, Wanfang, and China Biomedical Database to identify the eligible randomized controlled trials (RCTs) concerning using PNS to treat elderly people with stroke from their inception to first, May 2022. Meta-analysis was used for pool analysis of the included studies, whose quality was assessed via Cochrane Collaboration's RCT risk of bias tool. Results Altogether 206 studies published between 1999 and 2022 with a low risk of bias were included, covering 21,759 participants. The results showed that the improved neurological status shown in the intervention group with PNS alone was statistically significant (SMD = −0.826, 95% CI: −0.946 to −0.707) in contrast to the control group. The total clinical efficacy (Relative risk (RR) = 1.197, 95% Confidence interval (CI): 1.165 to 1.229) and daily living activities (SMD = 1.675, 95% C: 1.218 to 2.133) of elderly stroke patients were significantly improved as well. In addition, the invention group using PNS combined with WM/TAU displayed significant improvement in neurological status (SMD = −1.142, 95% CI: −1.295 to −0.990) and the total clinical efficacy (RR = 1.191, 95% CI: 1.165 to 1.217) compared with the control group. Conclusion Single PNS intervention or PNS combined with WM/TAU significantly improves the neurological status, the overall clinical efficacy and daily living activities of elderly stroke patients. However, more multicenter RCT research with high quality is required in the future to verify the results in this study. The trial registration number: Inplasy protocol 202330042. doi:10.37766/inplasy2023.3.0042.


Introduction
Stroke, a major cause of disability and death, is a common disease among elderly people. As the second cause of death among people aged over 60 around the world, its mortality is on the rise every year. China has the highest incidence of stroke, where 1,763 out of 100,000 people sufer from ischemic stroke per year [1]. Meanwhile, disability rate of stroke is as high as 75% in China [2]. According to a report from Global Burden of Disease, 1.7 million people died from stroke in 2010 [3]. In recent years, stroke has become the frst cause of death in China [4]. According to statistics, from 2015 to 2018, around 2% of people over 40 years old had a stroke, up to 50% of whom were no more than 64, which suggest that the average age of stroke onset is going down. With a high rate of prevalence, disability and mortality, stroke has thus become a global public health concern.
Internationally, the main treatment adopted now for stroke is still vascular recanalization (thrombolysis and endovascular interventional therapy), whose efect [5,6], however, is enjoyed by only a few patients due to factors such as short time window, high cost, and limited medical level. Panax notoginseng saponins (PNS), with the functions of dispersing blood stasis and hemostasis, reducing swelling and relieving pain, is widely used for treating stroke in China. Modern pharmacological studies believe that PNS can reduce the infarct size of ischemic stroke, inhibit edema [7], protect the blood-brain barrier, reduce nerve damage, and inhibit relevant infammation [8,9]. Commonly used PNS products mainly include oral-type products, such as Xueshuantong capsule (XC), Xuesaitong soft capsule (XSC), Sanqi Tongshu capsule (STC), and compound Xueshuantong capsule (CXC), and injection type products, such as Xueshuantong capsule, Xuesaitong soft capsule, Sanqi Tongshu capsule, and compound Xueshuantong capsule.
With the increase of age, the elderly are more susceptible to stroke hemiplegia because of gradually declining body function and continually weakening cardiovascular system. For these patients, Western medicine (WM) often adopts recovery treatment that helps improve movement function to a certain extent, but rehabilitation cannot be achieved [10]. Although PNS has been extensively used for treating stroke and many clinical trials have confrmed its clinical efcacy and safety [11,12], whether it is efective and safe for the elderly population remains to be investigated. However, related evidence-based studies for this age group were rarely reported and the majority of previous studies measured only a single stroke outcome (eg., clinical efcacy). Furthermore, Duplicate records removed (n = 191) Records marked as ineligible by automation tools (n = 0) Records removed for other reasons (n = 0)

Identification of studies via databases and registers
Records excluded** (n = 4806) Reports not retrived (n = 219) Reports excluded:120 Studies were not RCT (n =4) Studies were not report their available data (n =89) Studies without appropriate outcomes (n =17) Studies were enrolled participants age below 60 (n=10)         there were many problems with the methodological quality of previous studies. For instance, the studies included had low quality and serious bias, which may adversely afect the credibility of evidence and confuse subsequent clinical practice and health decision-making. As a result, this study, targeting at the elderly population, comprehensively analyzed the efcacy and safety of PNS in multiple outcomes by meta-analysis in order to provide more systematic clinical evidence for clinical medication and health decision-making concerning elderly stroke patients.

Methods
Tis study was reported in strict accordance with the Priority Reporting Item for Systematic Reviews and Meta-Analysis (PRISMA) [13]. All the analyses were based on previously published studies, and therefore, no ethical approval and participants' consent were required. Study on the efect of Xueshuantong combined with edaravone in treating elderly patients with acute cerebral infarction and its infuence on cytokines, cerebral hemodynamics, and vascular endothelial function Evidence-Based Complementary and Alternative Medicine            Evidence-Based Complementary and Alternative Medicine search was performed based on the combination of subject words and free words. Te Chinese search terms included stroke, cerebral infarction, cerebral embolism, cerebral apoplexy, ischemic stroke, ischemic stroke, Panax notoginseng saponins, blood embolism Tong, Xueshuantong, Sanqi Tongshu Capsules, and randomized controlled trials. Te English search terms were Xueshuantong capsule, Sanqi Tongshu capsule, Xuesaitong soft capsule, brain infarction, compound Xueshuantong, cerebral infarction, stroke, brain embolism, ischemic stroke, cerebrovascular disorders, and RCT. Te specifc search strategies of each database were attached in Appendix. After the initial search, the collected studies were screened to remove duplicates. Ineligible articles were fltered out according to their titles and abstracts. For the remaining potentially relevant results, their full texts were reviewed and assessed according to our screening criteria, during which ineligible articles were excluded, numbered, and then registered with the reasons why they were ruled out. For texts with incomplete information or problems, we evaluated their eligibility after contacting the author.

Inclusion and Exclusion Criteria.
In this study, the screening criteria conformed with the PICOS (population, intervention, comparators, outcomes, and study design) principles of the Cochrane Collaboration to assess the quality of studies. Detailed information is listed below.  [14]. Te subject groups were older adults with an average age of over 60, regardless of gender or race [15].

Intervention.
Intervention involves single use of PNS such as Xuesaitong injection, Xueshuantong injection, Lulutong injection, Sanqitongshu capsule, Xuesaitong soft capsule, Xuesaitong Tablets, Xueshuantong Capsules, and Xuesaitong Dropping Pills, combined use of PNS and WM or PNS and treatment as usual (TAU).

Comparator.
All the patients in the controlled group underwent conventional routine treatment to improve their cerebral blood supply and drug treatment, such as taking medication to nourish their brain tissues. Conventional therapy in WM, which followed Chinese Guidelines for the       Diagnosis and Treatment of Acute Ischemic Stroke 2015 [5], includes intravenous thrombolysis, endovascular therapy, antiplatelet, anticoagulation, decrease of fbrinogen, increase of blood volume, improvement of cerebral circulation, nutrition of nerves, lipid regulation, blood pressure reduction, hypoglycemia, and rehabilitation. Te regular treatments for the controlled groups and the treated groups must be the same, and the course of treatment is not limited.

Outcomes.
Measurement for the outcomes should be clearly defned and includes at least one of the following items: neurological defcit score, the clinical response rate, and assessment of activities of daily living (ADLs).

Study Design.
All the included studies were RCTs or clinical controlled trials. Te study design adopted RCT. In other words, "random grouping" should be mentioned in the article or its grouping method was "tossing a coin," "drawing lots," "rolling dice," "random number table," "computer coding," "block randomization," or "stratifed randomization."

Exclusion
Criteria. Exclusion criteria were as follows: (1) (1) overall clinical response rate [16] and (2) posttreatment ADL score. Te included studies were numbered for the convenience of reviewing. Basic information and data in these studies consisted of title, authors, publication year, specifc treatments, number of cases, sample ages, male to female ratio, experimental design methodologies (including randomized method, blind method and the like), key factors for evaluating risk of bias, the outcome measures and the results, the course of treatment, etc.

Quality Assessment of the Included Studies. Te risk of bias in the included studies was assessed via the Cochrane
Collaboration's RCT risk of bias tool [17]. Tere were 7 assessed items random sequence generation, allocation concealment, blinding of participants and intervention providers, blinding of outcome assessors, outcome

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Evidence-Based Complementary and Alternative Medicine completeness, selective reporting of outcomes, and other sources of bias, which were rated as low, and unclear or high bias level. Te assessment of included RCTs was separately conducted by two researchers, who then exchanged the results and checked. Disagreement would frst be discussed by the two researchers, who would refer to the supervision researcher if they could not reach a consensus. Finally, the risk of bias map was drawn with RevManand Ofce software.

Statistical Analyses.
Categorical data (such as the overall clinical response rate) were to be combined and measured by relative risk (RR) and numerical data (such as neurological defcit score, and the activity of daily living score) by standard mean diference (SMD), whose 95% of confdence interval (CI) was calculated. Te heterogeneity of the included studies was measured by the chi-square test (with a signifcant level of 0.1) and judged by the value of I 2 at the same time. During the meta-analysis, when statistically signifcant heterogeneity (P < 0.10 or I 2 > 50%) was shown, the random efect model would be chosen; otherwise, (P ≥ 0.10 or I 2 ≤ 50%) the fxed efect model would be applied [18]. For signifcant heterogeneity, subgroup, or sensitivity analysis or only descriptive analysis was conducted to deal with the data. If more than ten studies were concerned with one certain variable, the publication bias would be assessed by a funnel plot and Egger's test [19]. Te above data analyses were done with the help of Software STATA (Version 14.0, Stata, Corp, College Station, TX).

Literature Screening.
Te initial database search yielded 5,542 articles and 5,351 remained after removing duplicates by Endnote. Ten, 545 articles were removed by checking titles and abstracts, and 120 articles were excluded from the rest after the full text review. Finally, 206 eligible papers were included for quantitative analysis. Te detailed information on literature screening is presented in Figure 1 [13,20].

Characteristics of the Included Studies.
Tis study collected 206 RCTs for analysis, with 21,759 participants involved, among whom 11,118 were randomly distributed in the intervention group and 10,641 in the controlled group. All included articles were published between 1999 and 2022, 204 of which are Chinese. Te average age of participants was 63.20 years old with 12,502 male participants, accounting for 57.46%. Te course of treatment varied from 3 days to 6 months. 108 studies reported acute stroke period,    Table 1 for all basic information on the included studies.

Quality Assessment.
All of the 206 articles were RCTs, which were considered low risk of bias in the generation of random sequences. Without clarifying allocation concealment, 143 articles were rated unclear risk of bias. 15 articles reported blinding of participants and 41 used blinding for assessors. All included studies were at low risk of bias in terms of outcome completeness. 7 articles were rated as low risk for selective reporting bias. For other bias, 38 and 168 studies were at unclear and low risk of bias, separately. Detailed information on the quality assessment of the included studies were introduced in Table 2 and Figure 2. Moreover, certainty assessment of the included studies was shown in Table 3.

Secondary Outcomes: Total Clinical Efcacy.
Tere were 77 articles reporting the outcomes of overall clinical efcacy for using PNS alone, involving 8,589 participants. Our results indicated that, compared to the controlled group, the overall clinical efcacy of the PNS alone group showed statistically signifcant diference (RR � 1.191, 95% CI: 1.165 to 1.217; I 2 � 52.9%, P heterogeneity <0.001) ( Table 4 and Figure 7). Te funnel plot and Egger's test results revealed hint of publication bias (P < 0.001) (Figure 8).
For the intervention group using PNS combined with WM/TAU, 100 articles reported the outcome of overall clinical efcacy, with 10,249 participants involved. Compared with the controlled group, there was statistical signifcance in the overall clinical efcacy of PNS combined with WM/TAU in treating elderly stoke (RR � 1.191, 95% CI: 1.165 to 1.217; I 2 � 42.8%, P heterogeneity <0.001), as shown in Table 4 and Figure 9. Hint of publication bias was observed in the funnel plot and Egger's test results (P < 0.001) ( Figure 10).
3.6. Activities of Daily Living Score. Tere were 11 articles reporting ADLs of 839 elderly stroke patients who were treated with PNS alone. As shown in Table 4, elderly stroke patients in the intervention group who were treated with PNS displayed signifcant improvement in their ADLs (RR � 1.675, 95% CI: 1.218 to 2.133; I 2 � 87.7%, P heterogeneity <0.001) ( Table 4 and Figure 11). Te funnel plot and Egger's test results hinted the existence of publication bias (P � 0.012) ( Figure 12).
As for the efect of PNS combined with WM/TAU on ADLs in elderly stroke patients (SMD � 1.034, 95% CI: 0.900 to 1.168; I 2 � 77.8%, P heterogeneity <0.001) ( Table 4 and Fig ure 13), 44 articles with 4,508 participants showed that compared to the controlled group, elderly stroke patients in the intervention group did not improve signifcantly. Te funnel plot and Egger's test results indicated hint of publication bias (P � 0.003) ( Figure 14).

Subgroup Analysis.
Due to the signifcant heterogeneity of total clinical efcacy, subgroup analysis was conducted based on the following variables: area (developed vs. developing areas), publication year (before vs. and after 2015),     Evidence-Based Complementary and Alternative Medicine sample size (less vs. no less than 100), and male to female ratio (below vs. not below one). Te analysis results showed that, for the single PNS intervention, heterogeneity mainly came from articles published before 2015 (Table 4). For the intervention group using PNS combined with WM/TAU, the primary source of heterogeneity was articles with a sample size of less than 100 or with a male to female ratio of less than 1. Results of the analyses revealed that the source of heterogeneity potentially correlated with publication year, treatment duration, and total sample size as well as region development condition. Te subgroup analysis results are shown in Table 4.

Discussion
In this study, 206 articles involving 21,759 participants were collected for meta-analysis. Te results showed that compared with the controlled group, single PNS or PNS combined with WM/TAU signifcantly improved the neurological status, overall clinical efcacy, and ADLs of elderly stroke patients.
In clinical treatment for ischemic stroke, antiplatelet, statin, and antihypertension were the three "cornerstones" [21]. However, the application of WM hit a bottleneck due to issues such as drug resistance, impairment of liver and kidney function, and interactions caused by the co-use of multiple drugs and the like. On the strength of traditional Chinese medicine theory and experience, Chinese medical workers have achieved favorable results in preventing and treating cerebrovascular diseases with natural medicines. After extensively reviewing and analyzing 206 PNS-related clinical trials, this study confrmed the efectiveness of PNS in the treatment of stroke in the elderly population and provided a theoretical basis for treating them in the feld of traditional Chinese medicine.
As a traditional Chinese medicine with a history of over 600 years, PNS has the functions of promoting blood circulation, removing blood stasis, reducing swelling, relieving pain, etc. PNS products, such as Sanqitongshu capsule, are mainly composed of panaxtriol saponins (PTS), a component in Sanqi capable of promoting blood circulation and removing blood stasis [22,23]. By now, the mechanism of PNS is still unclear. It is likely that PTS reduces endothelin levels in the peripheral blood, increases cerebral blood supply to ischemic areas, regulates blood hypercoagulability, and improves the microcirculation in ischemic brain tissue [24]. Te major active component in PTS, Rg1 (accounting for 60%), and R1 and Re (accounting for 20%), can improve cerebral ischemic dysfunction, restore ischemic cerebral metabolic abnormalities, resist platelet aggregation, and reduce blood viscosity in the treatment of cerebral arterial thrombosis. In addition, Rg1 enhances the activity of the fbrinolytic system, promotes the release of nitric oxide from the vascular endothelium, and thus, has an antithrombotic efect [25]. For ischemic reperfusion injury, PNS can reduce calcium overload, cerebral edema, and structural damage and promote nerve repair during reperfusion [26] and help reduce mortality during ischemicreperfusion. What is more, relevant studies show that PNS enhances the ischemic tolerance of the brain and reduces the recurrence of fatal ischemic brain injury, which is benefcial to the secondary prevention of ischemic stroke [27].
PNS has a wide range of pharmacological efects, including scavenging free radicals and antioxidative stress, inhibiting infammatory factors, blocking calcium ion channels, improving microcirculation and energy metabolism, etc. Tese efects account for the favorable results of PNS in the treatment of ischemic cerebrovascular disease. PNS can dilate cerebral blood vessels so that cerebrovascular resistance reduces and cerebral blood fow increases. For animals, experimental results indicated that mean blood pressure (BMP) and cerebrovascular resistance (CVR) of anaesthetized rabbits and rats are reduced after the intervention of PNS, depending on the dosage used, but their cerebral blood fow did not increase [28]. PNS for injection, made of Sanqi, has high bioavailability, rapid action, and defnite curative efect, which, however, is likely to cause adverse reactions, because it is complicatedly composed, the content of its active components and impurities is difcult to control, and it acts on multiple aspects of the brain.  Figure 12: ADL-SMD-Ran-funnel plot [1].pdf. 28 Evidence-Based Complementary and Alternative Medicine Terefore, it is essential to specify the ingredients and their doses in the injectable PNS so that the quality of the injection as well as the safety of patients can be ensured [28]. Related preparation research explained that compound Xueshuantong capsules efectively reduce blood viscosity, inhibit platelet activation and aggregation, enhance vasodilation regulation function, and increase fbrinase activity, thereby mitigating the cerebrovascular injury caused by oxidative stress response due to ischemic oxygen feeding. Additionally, compound Xueshuantong capsules reduce blood viscosity, regulate blood lipids, and block calcium ion channels, which is conducive to the recovery of cranial nerve function [29][30][31][32]. Oral PNS can be used for treating acute stroke by way of multi-target and multi-path. It can improve cerebral blood supply, repair nerve function, narrow the infarct size, and improve the clinical prognosis displaying the clinical advantages of traditional Chinese medicines. Subgroup analysis discovered that PNS intervention or PNS combined with WM/TAU improved the overall clinical efcacy, neurological status, and ADLs of elderly stroke  Evidence-Based Complementary and Alternative Medicine patients. Sources of heterogeneity probably came from articles with smaller sample sizes or older publications. Conclusions drawn from these articles were less reliable and the evidence was not fully updated, consequently giving rise to heterogeneity in our meta-analysis results.
To our knowledge, this is the frst meta-analysis of the clinical efcacy and safety of PNS in the treatment of elderly stroke patients. Based on extensive experimental data, this study made a scientifc and objective evaluation of the effcacy and safety of PNS in the treatment of acute elderly stroke. Additionally, clinical application of the study provided an objective and reliable evidence-based reference for the follow-up research, nursing staf, clinical workers, and health policy decision makers. However, there were some limitations. For one thing, some of the articles involved were of relatively low quality, with unclear randomization methods, allocation concealment, and uncalculated sample size, which afected the reliability of the conclusion in this study. For another, the fact that all the included studies are Chinese led to linguistic bias in the results. Terefore, followup studies should carefully be designed, implemented, and reported following the standard of RCTs [33]. Moreover, we found a moderate to high heterogeneity across our study, which might directly afect the reliability of our evidence. Although by implementing subgroup analyses based on the primary results, we identifed the sources of heterogeneity caused by diferent treatment duration and regional development condition in diferent literature, there were still other hidden elements afecting the measured efect of PNS in this study. Consequently, it is crucial to carry out multicenter and larger-sample RCTs on treating elderly stroke patients with PNS so as to provide guidance for clinical treatment and follow-up research.

Conclusion
Our study found that PNS intervention or PNS combined with WM/TAU signifcantly improved the neurological function, DLAs, and the overall clinical efcacy in elderly stroke patients. Considering the quality of the included studies, the results of this study should be interpreted with caution. And it is necessary to conduct more multi-center RCTs with high quality to explore the efcacy and safety of PNS for elderly stroke patients in the future, thus contributing more reliable primary data to evidence-based decision-making.